Transmission TH350 doesn't engage anymore - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Ventura76 · 03-29-2016, 07:52 PM

Hi guys

I was coming back home today after my daily one hour trip from the office (Highway and city).

Everything was OK until that last STOP sign. The car has started to drive normally but after 2 or 3 seconds I heard that strange sound (just like a bang on a saucepan) then nothing. Not in D, not in R. The car hold the park and I am able to shift but the transmission does not engage anymore.

The last two weeks, I had to wait at least 2 or 3 minutes for having the car to engage in D even with some transmission fluid refills.

Any ideas?

Thanks and sorry for my bad english

87Skier · 03-29-2016, 11:32 PM

Does it make any noise? Do the rpm's drop when you put it in gear? Is the fluid level correct? Is there an issue with the rear end (driveshaft turning and the rear end not)?

Beyond that, I would suspect a hard part failure. If it didn't make a noise, I would suspect a fluid pressure issue.

CSHADES · 03-30-2016, 09:15 AM

Just for the fun of it pull the flywheel cover off and make sure the torque convertor bolts didn't fall out of it. I bought a 1980 2wld in 1985 for a $1000 because the guy told me the trans was bad in it. I towed it home and was getting ready to pull the trans and there were no bolts in the convertor. Put some bolts in and I was driving it that afternoon.

GRADYS Performance · 03-30-2016, 11:58 AM

Checking the line pressure with a pressure gauge will tell you a lot about what is going on inside the transmission.

Ventura76 · 03-30-2016, 07:04 PM

Thanks guys!

Quote:

Does it make any noise?

Nothing at all

Quote:

Do the rpm's drop when you put it in gear?

No, the engine runs at an high idle speed, just like in Neutral

Quote:

Is the fluid level correct?

Looks like yes but today I was surprised to see that what I though to be water on the top of the air box finally looks more like burned transmission fluid. Can it be sprayed thru the dipstick?

Quote:

Is there an issue with the rear end (driveshaft turning and the rear end not)?

No

I will take a look under the car on Saturday and let you know

Ventura76 · 04-02-2016, 06:52 PM

Well, Went under the truck today.

Seems like a huge leak somewhere, everything is wet, oil pan, trans pan etc...(ATF fluid I think).

Shifter works fine. There is what I believe to be a normal sound in the transmission when the gear changes. If I put the R, D 1 or 2, I am able to move the truck forward by pushing it with my hands just like in Neutral.

I think I will have to remove the trans. Not sure that I want to that but....

03-29-2016, 07:52 PM	#1
Ventura76 Registered User Join Date: Oct 2015 Location: Quebec City Quebec Posts: 29	Transmission TH350 doesn't engage anymore Hi guys I was coming back home today after my daily one hour trip from the office (Highway and city). Everything was OK until that last STOP sign. The car has started to drive normally but after 2 or 3 seconds I heard that strange sound (just like a bang on a saucepan) then nothing. Not in D, not in R. The car hold the park and I am able to shift but the transmission does not engage anymore. The last two weeks, I had to wait at least 2 or 3 minutes for having the car to engage in D even with some transmission fluid refills. Any ideas? Thanks and sorry for my bad english

03-29-2016, 11:32 PM	#2
87Skier Registered User Join Date: Mar 2014 Location: Corvallis, OR Posts: 715	Re: Transmission TH350 doesn't engage anymore Does it make any noise? Do the rpm's drop when you put it in gear? Is the fluid level correct? Is there an issue with the rear end (driveshaft turning and the rear end not)? Beyond that, I would suspect a hard part failure. If it didn't make a noise, I would suspect a fluid pressure issue. __________________ 1972 GMC Jimmy Custom 4.8L (L20)/6L90E/NP205 1989 Chevy Suburban V2500 350/Turbo 400/4.11 gears 1996 Chevy Suburban K1500 350/4L60E

03-30-2016, 09:15 AM	#3
CSHADES Registered User Join Date: Nov 2015 Location: portage wi Posts: 506	Re: Transmission TH350 doesn't engage anymore Just for the fun of it pull the flywheel cover off and make sure the torque convertor bolts didn't fall out of it. I bought a 1980 2wld in 1985 for a $1000 because the guy told me the trans was bad in it. I towed it home and was getting ready to pull the trans and there were no bolts in the convertor. Put some bolts in and I was driving it that afternoon.

03-30-2016, 11:58 AM	#4
GRADYS Performance Registered User Join Date: Dec 2013 Location: Columbus, Oh Posts: 367	Re: Transmission TH350 doesn't engage anymore Checking the line pressure with a pressure gauge will tell you a lot about what is going on inside the transmission. Last edited by ETsC10; 03-30-2016 at 05:38 PM.

04-02-2016, 06:52 PM	#6
Ventura76 Registered User Join Date: Oct 2015 Location: Quebec City Quebec Posts: 29	Re: Transmission TH350 doesn't engage anymore Well, Went under the truck today. Seems like a huge leak somewhere, everything is wet, oil pan, trans pan etc...(ATF fluid I think). Shifter works fine. There is what I believe to be a normal sound in the transmission when the gear changes. If I put the R, D 1 or 2, I am able to move the truck forward by pushing it with my hands just like in Neutral. I think I will have to remove the trans. Not sure that I want to that but....



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